1. Field of the Invention
The invention relates to an optical device, more particularly to a beam splitting module and a light source system incorporating the beam splitting module.
2. Description of the Related Art
A beam splitter is used, for instance, for combining light beams traveling along first and second directions that are different from each other. One light beam traveling along the first direction impinges one side of the beam splitter at a 45-degree angle and passes through the beam splitter to continue traveling along the first direction. Another light beam traveling along the second direction impinges an opposite side of the beam splitter at a 45-degree angle and is reflected by the beam splitter to travel further along the first direction. To achieve the above, the beam splitter is disposed perpendicular to a plane defined by the first and second directions.
As shown in FIG. 1, in a conventional beam splitting module, a beam splitter 11 is supported by two pairs of supporting walls 12 so as to be disposed perpendicular to a base plate 13. Each supporting wall 12 has opposite surfaces 121 that are both perpendicular to the base plate 13. Light beams impinge the beam splitter 11 in directions parallel to the base plate 13.
It is necessary for an article and its mold to have a parting angle of, for instance, 1.5 to 2 degrees, therebetween so as to facilitate mold release when a normal plastic material is used to fabricate the article, i.e., the parting angle must be non-zero. However, since the opposite surfaces 121 of each supporting wall 12 are perpendicular to the base plate 13, a special material for use in zero-parting-angle situations, such as bulk molding compound (BMC), must be used when the supporting walls 12 and the base plate 13 are to be formed integrally. This way, the integrally formed supporting walls 12 and base plate 13 are released from their mold in a parting direction that is parallel to the surfaces 121 of the supporting walls 12.
Due to this perpendicular relationship between the base plate 13 and the supporting walls 12, the fabrication material thereof is limited to the special material for use in zero-parting-angle situations, thereby increasing fabrication cost of the conventional beam splitting module. In addition, since BMC is a thermosetting plastic material, which cannot be recycled after use, the conventional beam splitting module is not environmentally friendly.